This invention relates in general to pivot devices for doors and more particularly to a pivot arrangement capable of transmitting pressurized air into a door.
SOME DOORS ARE PROVIDED WITH AIR-OPERATED APPLIANCES, AND TO ACTUATE THESE APPLIANCES PRESSURIZED AIR MUST BE INTRODUCED INTO THE DOOR FROM THE SURROUNDING FRAME. For example, a door may be provided with an air-operated door opener which is supplied with air when a panic bar or handle on the door is depressed to assist an individual opening the door. Likewise, the door may be provided with an air-operated lock or an air cylinder to hold the door open in an emergency. Some air-operated appliances for doors are illustrated in U.S. patent application Ser. No. 492,445 of Francis C. Peterson, filed July 29, 1974 and entitled DOOR EXIT FIXTURE WITH PHEUMATIC MEANS FOR MAINTAINING A LATCH BOLT IN ITS RETRACTED POSITION, and in U.S. patent application Ser. No. 533,961 of Francis C. Peterson, filed Dec. 18, l974 and entitled ENTRY STRUCTURE AND AIR-OPERATED LOCK THEREFOR.
The principal advantage of pneumatically operated door appliances over electrically operated appliances is that the former operate without conducting electrical current through the door. In this connection, it should be noted that many building codes severely limit the magnitude of electrical voltage and current which may be introduced into a door circuit, and usually the maximum voltage and current are enough to operate only a very light solenoid. These solenoids do not develop enough force power for most door mounted appliances.
The normal procedure for introducing air into a door to operate door mounted appliances is to install a looped hose between the hinge jamb and the adjoining side of the door. This hose, of course, flexes as the door is opened and closed, and the flexure is particularly pronounced with so called pivot doors which possess the capability of swinging in both directions out of the door opening. The constant flexing eventually causes the hose to crack. Moreover, the flexible hose is exposed where it can be tampered with or inadvertently torn loose.